A newly released US Secret Service audiotape from the attempted assassination of Ronald Reagan sheds light on the chaotic aftermath when neither the president nor his bodyguards realised he had been shot.

In the 10-minute tape from 30 March 1981 agents at the scene are heard telling their command post that shots were fired and people were injured but "Rawhide's all right" and was being rushed back to the security of the White House. Rawhide was Reagan's Secret Service code name.

Suddenly, one agent reports that the president's limousine is changing course to George Washington University hospital and another agent says: "Let's hustle."

The Secret Service released the tape on Friday in response to a public records request by Del Wilber, author of a book on the shooting due to be published next week.